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Tuesday, January 15, 2013

Pterribly good scabious....the petite Pterocephalus

Scabiosa caucasica

There is something charmingly old fashioned about scabiosas:
the homespun shape of their nosegay flowers flowers (lilacs, purples, smouldering gray blues), looking for all the world as though
they’d been fashioned at a quilting bee. There are a host of stately
scabious—like Scabiosa caucasica—that
grace all self respecting perennial borders and even a good many xeric
Mediterranean sorts that are perfect for the xeriscape. Let's not even mention
Cephalarias, the Goliaths of the Garden, begging for some David with a spade to
take them out! There are a rabble of relatively compact, long blooming
scabiosas that are often planted in rock gardens. Some of these have been among
the most beautiful of rapacious weeds I have ever introduced to the Rock Alpine
Garden. Let’s just say, anything labeled S.
lucida or S. columbaria should be
approached with great caution and a bottle of roundup handy. There are forms
that are incredibly cute, compact, evergreen that bloom from spring to fall and
will soon fill every nook and cranny of your garden with their progeny. Caveat Emptor!

And then there’s Pterocephalus,
a genus closely allied to Scabiosa,
only proffering everything a rock gardener’s heart could desire. These form
silvery or woolly or deeply divided bright green mats that spread slowly to
cover a large area in time. Their flowers are typical scabious, sometimes
produced in considerable quantities throughout the warmer months. This genus
encompasses plants with a variety of sizes and shapes: there are coarse Pterocephalus that abound in the higher
reaches of Asia. Many are weedy looking and unattractive. We shall ignore
these… Thus far I have grown three miniatures that are among my most treasured
alpines. A fourth shimmers and hovers before me in my imagination, like
Dulcinea did for Don Quixote, like a holy grail. We shall get to that one in a
minute…

Pterocephalus depressus

The first species I saw was in the garden of Eric and Mabel Hilton, famous alpine growers who lived above the Severn near Bristol in the west of England. Eric’s expansive garden had hundreds of treasures, including a large mat of Pterocephalus depressus, which I subsequently discovered came from Morocco. I never dreamed that there were that many hardy plants in Morocco (except for Atlas daisy—the exception that proves the rule). I had to have this plant. Eric came to visit me a year later, and brought a rooted cutting along as a present. That cutting has given rise to all the plants of this wonderful groundcover growing in America today, I am quite sure.

The foliage on this species is the deepest pinnatifid (deeply cut in English) and a brighter green than the other two species I grow. The flowers are an especially lovely dark, dusky rose color—very Victorian don’t you think? It blooms and blooms and blooms, making a perfect picture all summer long when we desperately need color. My original plants put in my old house on Eudora in 1986 have spread over a meter in extent. The old stems have become veritably bonsai-like, woody and gnarly and very picturesque. This has taken over 20 years—a testament to the toughness of this plant. It should be in every Colorado rock garden. Since it is easily divided and roots with ease, there’s no excuse for you not to have this gem!

Pterocephalus parnasii

The Greek species (Pterocephalus parnassii) named for Mt. Parnassus where I looked for it in vain, is by far the silveriest foliage of the three—very hairy and gray. I find this the trickiest of the three kinds I grow: it’s good to keep this in propagation. It seems to be especially intolerant of too much water. It has typical dusky, scabious flowers of a pale lilac pink. They are nicer than they sound. This blooms primarily in the spring, with only an occasional late summer flower. I wish I could find a perfect spot to grow this. I keep it four or five years, and then it tends to fade away—probably wanting to go back to Greece where the winters are a tad milder? It is worth the effort to tame it. It has gone by various other epithets, such as P. perennis, so do not be fooled when you look for this one. It is a classic alpine well known in the literature.

Pterocephalus pinardii

Not so its Turkish cousin, Pterocephalus pinardii, which seems to have only been recently
introduced from Turkey. This is quite variable in my experience: unlike the
previous two, which probably only represent a single clone that has been in
cultivation for many decades, most plants of P. pinardii are grown from wild seed, and we are seeing the whole
spectrum of variability in this that one would expect of a wildflower from
brightly colored to dull individuals, fast spreading mats to clumping forms,
and foliage in many shades of gray green. It seems to be exactly intermediate
beween P. parnassii and P. depressus in some ways, but well
worth growing in its own right.While
not as indestructible as the Moroccan species, it is tougher than the Greek (as
one would expect of those roughhousing Turks!).

But here is a fourth species I have never grown—although I
have germinated a few seedlings that damped off, come to think of it. That is Pterocephalus spatulatus. This has
smaller, smoother edged leaves than any of the species mentioned thus far. It makes intensely tight mounds and mats on the harshest
limestone cliffs and barrens in the high Cazorla Mountains and elswhere too in
Andalucia. Spain. The color of the foliage is blindingly, brilliant white
with tomentose hairs delicious to the touch, delicious to the eyes. No I do not
eat my plants, so I don’t know if it’s delicious to the palate. The flowers are
bright pink, and there is no doubt this is the crown jewel of the genus.

I have trod upon it and admired the gnarly mats in its
native National Park. Not far away, dozens of bright purple Crocus serotinus lay wilting in the
noonday sun, dug up by wild boars who ate their corms in the night. Giant,
windswept misnamed Austrian pines grew gauntly here and there nearby. I
searched and searched in vain for a single seed to take back as a memento, and
was skunked. I thought I heard a little chuckle as I turned to walk
away—probably just the Spanish wind whistling in the Spanish Pinus nigra.

[Adapted from a short piece originally published in Saximontana, newsletter of the Rocky Mountain Chapter of the North American Rock Garden Society]